Posted on 2008-07-01 10:02
T.S Liu 閱讀(894)
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linux_bug_tool
Valgrind 是在linux系統(tǒng)下開發(fā)應(yīng)用程序時(shí)用于調(diào)試內(nèi)存問題的工具。它尤其擅長(zhǎng)發(fā)現(xiàn)內(nèi)存管理的問題，它可以檢查程序運(yùn)行時(shí)的內(nèi)存泄漏問題。
它的官方網(wǎng)址是 http://www.valgrind.org/
下載最新版本的Valgrind，目前是3.2.0。 wget http://www.valgrind.org/downloads/valkyrie-1.2.0.tar.bz2
執(zhí)行常規(guī)的安裝步驟：./confgure && make && make install。注意： 系統(tǒng)必須安裝QT的開發(fā)包。即便這樣在make 時(shí)還是出現(xiàn)qplatformdefs.h這個(gè)文件找不到的情況，導(dǎo)致make失敗。查找系統(tǒng)中的qplatformdefs.h 之后，發(fā)現(xiàn)沒有存在于qt的標(biāo)準(zhǔn)頭文件目錄/usr/lib/qt-3.3/include。如是將/usr/lib/qt-3.3/mkspecs/linux-g++/ 目錄下該頭文件復(fù)制標(biāo)準(zhǔn)頭文件目錄，重新make ，后面一切OK。
初次使用
編譯如下代碼: gcc -Wall example.c -g -o example
#include <stdlib.h>
void f(void)
{
int* x = malloc(10 * sizeof(int));
x[10] = 0; // problem 1: heap block overrun
} // problem 2: memory leak -- x not freed
int main(void)
{
f();
return 0;
}
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注意：gcc 的-g 選項(xiàng)讓Valgrind調(diào)試輸出時(shí)指出相應(yīng)信息的代碼所在的行號(hào)。
| valgrind --tool=memcheck --leak-check=yes ./example |
==6742== Memcheck, a memory error detector for x86-linux.
==6742== Copyright (C) 2002-2004, and GNU GPL'd, by Julian Seward et al.
==6742== Using valgrind-2.2.0, a program supervision framework for x86-linux.
==6742== Copyright (C) 2000-2004, and GNU GPL'd, by Julian Seward et al.
==6742== For more details, rerun with: -v
==6742==
==6742== Invalid write of size 4
==6742== at 0x8048384: f (example.c:6)
==6742== by 0x80483AC: main (example.c:12)
==6742== Address 0x1B908050 is 0 bytes after a block of size 40 alloc'd
==6742== at 0x1B904984: malloc (vg_replace_malloc.c:131)
==6742== by 0x8048377: f (example.c:5)
==6742== by 0x80483AC: main (example.c:12)
==6742==
==6742== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 12 from 1)
==6742== malloc/free: in use at exit: 40 bytes in 1 blocks.
==6742== malloc/free: 1 allocs, 0 frees, 40 bytes allocated.
==6742== For counts of detected errors, rerun with: -v
==6742== searching for pointers to 1 not-freed blocks.
==6742== checked 1360800 bytes.
==6742==
==6742==
==6742== 40 bytes in 1 blocks are definitely lost in loss record 1 of 1
==6742== at 0x1B904984: malloc (vg_replace_malloc.c:131)
==6742== by 0x8048377: f (example.c:5)
==6742== by 0x80483AC: main (example.c:12)
==6742==
==6742== LEAK SUMMARY:
==6742== definitely lost: 40 bytes in 1 blocks.
==6742== possibly lost: 0 bytes in 0 blocks.
==6742== still reachable: 0 bytes in 0 blocks.
==6742== suppressed: 0 bytes in 0 blocks.
==6742== Reachable blocks (those to which a pointer was found) are not shown.
==6742== To see them, rerun with: --show-reachable=yes |
上面的C程序存在兩個(gè)錯(cuò)誤：1. 數(shù)組下標(biāo)越界；2. 分配的內(nèi)存沒有釋放，存在內(nèi)存泄露的問題。對(duì)于錯(cuò)誤1，看Valgrind的調(diào)試信息片斷
==6742== Invalid write of size 4
==6742== at 0x8048384: f (example.c:6)
==6742== by 0x80483AC: main (example.c:12)
==6742== Address 0x1B908050 is 0 bytes after a block of size 40 alloc'd
==6742== at 0x1B904984: malloc (vg_replace_malloc.c:131)
==6742== by 0x8048377: f (example.c:5) |
對(duì)于錯(cuò)誤2，看這個(gè)
|
==6742== malloc/free: 1 allocs, 0 frees, 40 bytes allocated.
......
==6742== 40 bytes in 1 blocks are definitely lost in loss record 1 of 1
==6742== at 0x1B904984: malloc (vg_replace_malloc.c:131)
==6742== by 0x8048377: f (example.c:5)
==6742== by 0x80483AC: main (example.c:12)
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